Note: Descriptions are shown in the official language in which they were submitted.
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COOLING SYSTEMS FOR USE ON AIRCRAFT
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR
DEVELOPMENT
[0001] This inventive subject matter was made with Government support under
F33615-03-D-2355-0006 awarded by the United States Air Force. The Government
has certain rights in this inventive subject matter.
TECHNICAL FIELD
[00021 The inventive subject matter relates to cooling systems and, more
particularly, to cooling systems for use on aircraft.
BACKGROUND
100031 A gas turbine engine may be used to power various types of vehicles and
systems. A particular type of gas turbine engine that may be used to power
aircraft is
a turbofan gas turbine engine. A turbofan gas turbine engine may include, for
example, a fan section, a compressor section, a combustor section, a turbine
section,
and an exhaust section. The fan section is positioned at the front, or "inlet"
section of
the engine, and includes a fan that induces air from the surrounding
environment into
the engine, and compresses a fraction of this air into the compressor section.
The
remaining fraction of air induced into the fan section is compressed into and
through a
bypass duct, and expanded out the exhaust section to produce thrust.
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[0004] The compressor section further raises the pressure of the air it
receives
from the fan section to a relatively high level. In a multi-spool engine, the
compressor section may include two or more compressors, such as, for example,
a
bigh pressure compressor and a low pressure compressor. The compressed air
from
the compressor section then enters the combustor section, where fuel nozzles
inject a
steady stream of fuel into a plenum formed by liner walls and a dome. The
injected
fuel is ignited in the combustor, which significantly increases the energy of
the
compressed air. The high-energy, compressed air from the combustor section
then
flows into and through the turbine section, causing rotationally mounted
turbine
blades to rotate and generate energy. The air exiting the turbine section is
exhausted
from the engine via the exhaust section, and the energy remaining in the
exhaust air
aids the thrust generated by the air flowing through the bypass duct.
[0005] Gas turbine engines may be configured to divert a portion of the high-
energy, compressed air from the compressor section for use in other aircraft
systems.
For example, some of the diverted air may be used for an aircraft
environmental
control system (ECS), an aircraft anti ice system, or other system. To ensure
that the
diverted air can be used for the aircraft systems, it is typically precooled
by a heat
exchanger or an air conditioning system. Conventionally, the heat exchanger or
air
conditioning system may be disposed in a section of the aircraft that is not
adjacent to
the engine. As a result, additional ducting and components are typically used
to flow
the diverted air to the heat exchanger or air conditioning system. However,
the
additional ducting and components may add unwanted weight and cost to the
aircraft,
which may be undesirable as the demand for more economical aircraft continues
to
increase.
[0006] Hence, there is a need for a cooling system that may be implemented
into
existing aircraft without substantially increasing weight and cost. Moreover,
it is
desirable to have a cooling system that may be implemented by adding a minimal
number of additional components to the aircraft.
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BRIEF SUMMARY
100071 The inventive subject matter provides cooling systems for aircraft.
100081 In one embodiment, and by way of example only, a system includes an
engine nacelle, an engine, a bypass duct, and a heat exchanger. The engine
nacelle
includes an airflow inlet. The engine is housed in the engine nacelle in flow
communication with the airflow inlet. The bypass duct extends between the
engine
nacelle and the engine is in flow communication with the airflow inlet. The
bypass
duct includes an outer wall having an opening formed therein. The heat
exchanger is
integrated with the engine and is disposed over the opening of the bypass duct
outer
wall between the bypass duct outer wall and the engine nacelle.
(00091 In another embodiment, and by way of example only, the system includes
an engine nacelle, an engine, a bypass duct, a heat exchanger, and a bypass
flow path
valve. The engine nacelle includes an airflow inlet. The engine is housed in
the
engine nacelle in flow communication with the airflow inlet. The bypass duct
extends
between the engine nacelle and the engine in flow communication with the
airflow
inlet and includes an outer wall having an opening formed therein. The heat
exchanger is disposed on the bypass duct outer wall in communication with the
opening thereof and including a bypass flow path air inlet, an engine air
inlet, a first
outlet, and a second outlet. The bypass flow path air inlet is in flow
communication
with the bypass flow path and the first outlet, and the engine air inlet is in
flow
communication with the engine and the second outlet. The bypass flow path
valve is
disposed downstream of the bypass flow path air inlet and is configured to
selectively
open and close to at least partially regulate airflow through the heat
exchanger.
(0010] In still another embodiment, and by way of example only, a system
includes an engine nacelle, an engine, a bypass duct, and a heat exchanger.
The
engine nacelle includes an airflow inlet. The engine is housed in the engine
nacelle in
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flow communication with the airflow inlet. The bypass duct extends between the
engine nacelle and the engine in flow communication with the airflow inlet,
and the
bypass duct includes an outer wall having an opening formed therein. The heat
exchanger is disposed between the bypass duct outer wall and the engine
nacelle and
has a wall that is integrally fonmed with the bypass duct outer wall. The heat
exchanger is in flow communication with the bypass duct outer wall opening and
includes a bypass flow path air inlet, an engine air inlet, a first outlet,
and a second
outlet. The bypass flow path air inlet provides flow communication between the
bypass flow path and the first outlet, and the engine air inlet provides flow
communication between the engine and the second outlet.
[0011] Other independent features and advantages of the systenis will become
apparent from the following detailed description, taken in conjunction with
the
accompanying drawings which illustrate, by way of example, the principles of
the
inventive subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
100121 FIG. 1 is a cross-sectional side view of a portion of an aircraft
including a
cooling system, according to an embodiment.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[00131 The following detailed description of the inventive subject matter is
merely
exemplary in nature and is not intended to limit the inventive subject matter
or the
application and uses of the inventive subject matter. Furthermore, there is no
intention to be bound by any theory presented in the preceding background of
the
inventive subject matter or the following detailed description of the
inventive subject
matter.
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100141 FIG. I is a simplified, cross-sectional view of a portion of an
aircraft 100
that includes a cooling system 102, according to an embodiment. The aircraft
100
may include an engine 101 housed in an engine nacelle 103. The engine 101
includes
a fan section 104, a compressor section 106, a combustion section 108, a
turbine
section 110, and an exhaust section 112. The engine nacelle 103 has an airflow
inlet
114 that provides air to the fan section 104. The air may be drawn into and
compressed through the fan section 104 via a fan 116. Part of the compressed
air
exhausted from the fan 116 is directed through a bypass duct 119 that has an
inner
wall 121 and an outer wall 123 that defmes a bypass flow path 120
therebetween.
The bypass duct 119 extends through the engine nacelle 103, and may be located
radially outwardly from the compressor section 106, the combustion section
108, the
turbine section 110, and the exhaust section 112. In an embodiment, a portion
of the
air flowing through the bypass flow path 120 may be exhausted out an opening
124
formed in the outer wall 123 of the bypass duct 119. Another portion of the
air may
be exhausted into a mixing duct 125 and expelled out of a nozzle exit 122. The
remaining fraction of air exhausted from the fan 116 is directed into the
compressor
section 106.
[00151 The compressor section 106 may include series of compressors 118, which
raise the pressure and increase the temperature of the air directed into it
from the fan
116. For example, the air pressure may have a pressure greater than about 300
psi and
a temperature greater than about 535 C. The compressors 118 may direct the
compressed air into the combustion section 108. In the combustion section 108,
whicb may include an annular combustor 126, the high pressure air is mixed
with fuel
and combusted. The combusted air is then directed into the turbine section
110.
[00161 The turbine section 110 may include a series of turbines 128, which may
be
disposed in axial flow series. The combusted air from the combustion section
108
expands through the turbines 128, causing them to rotate. The air is then
exhausted
through a mixer nozzle 129 and combines with air from the bypass duct 119 that
may
be in the mixing duct 125. The mixed air exits through a propulsion nozzle 130
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disposed in the exhaust section 112, providing forward thrust. It will be
appreciated
that although a long cowl mixing duct installation is shown, any other
configuration
may alternatively be employed. For example, a co-annular nozzle could
alternatively
be used in which the air from the bypass duct 119 and air from the mixer
nozzle 129
exit the engine 101 separately. In an embodiment, the turbines 128 rotate to
thereby
drive equipment in the engine 101, such as the compressor 118, via
concentrically
disposed shafts 132.
100171 The cooling system 102 diverts a portion of the compressed, high
temperature air from the compressor 118 and cools the diverted air before it
is
directed to other sections of the aircraft 100. In this regard, the cooling
system 102
includes a heat exchanger 136 that is disposed between the bypass duct 119 and
the
engine nacelle 103. In an embodiment, the heat exchanger 136 is integrated
into the
engine 101 and includes a wall that is integrally formed with the outer wall
123 of the
bypass duct 119. In another embodiment, the heat exchanger 136 may be a
separate
component that is coupled to the bypass duct outer wall 123 and positioned
over the
outer wall opening 124.
[00181 The heat exchanger 136 includes a bypass flow path air inlet 140, a
bypass
flow path air outlet 142, an engine air inlet 144, an engine air outlet 146,
and a core
155. The bypass flow path air inlet 140 is in flow communication with the
bypass
flow path 120 and may also communicate with the engine nacelle opening 124. In
another embodiment, a plurality of fms 150, which may or may not extend into
the
bypass flow path 120, are disposed in the bypass flow path air inlet 140 to
encourage
air from the bypass flow path 120 to flow into the heat exchanger 136. For
example,
one or more of the fins 150 may extend from the heat exchanger 136 and may
include
an angled flange 152 extending into the bypass flow path 120 configured to
direct air
toward the heat exchanger 136. Although seven fins are shown, it will be
appreciated
that a different number may alternatively be included. The bypass flow path
air inlet
140 is also in flow conzmunication with the bypass flow path air outlet 142
through a
cold side of the heat exchanger core 155 via a duct (not shown).
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100191 The engine air inlet 144 is in flow communication with one or more
sections
of the engine 101 (e.g., compressor section 106) and receives compressed, high
temperature air therefrom. In an embodiment, an engine air supply line 154
extends
between the compressor section 106 and the engine air inlet 144 to thereby
supply
compressed, high temperature air to the heat exchanger 136. Although shown as
a
pipe, the engine air supply line 154 may alternatively be a duct or other
structure
suitable for delivering air to the heat exchanger 136. The engine air inlet
144 also
communicates with the engine air outlet 146 through a hot side of the heat
exchanger
core 155 via a duct (not shown).
[0020] Cool air from the bypass flow path air inlet 140 enters the cold side
of the
heat exchanger and hot air from the engine air inlet 144 is directed into the
hot side of
the heat exchanger 136. The cold and hot air are separated from each other in
the heat
exchanger. In an embodiment, the heat exchanger core 155 may be made up of a
plurality of fins that separate the air. The fins may promote exchange of heat
from the
hot air of the engine 101 to the relatively cold air of the bypass duct 119.
The bypass
duct air that has been used to cool the hot air is then exhausted overboard
167 via, for
example, a duct 169. The cooled engine air may then be delivered to another
aircraft
system 164, such as an air conditioning system or an aircraft cabin via a
bleed air
supply line 156.
[0021] To regulate the air flow through the heat exchanger 136, one or more
valves
may be included in the cooling system 102. The valves may be any one of
numerous
types of valves capable of being disposed in a duct, or other suitable
structure, and
configured to selectively open and close to thereby regulate airflow and
pressure
therethrough. Additionally, the valves may be electrically, manually,
pneumatically,
or hydraulically operated.
[0022) In an embodiment, one or more bypass flow path valves (e.g., valve 162)
may be disposed in the cooling system 102 downstream of the bypass flow path
120
to thereby regulate air flow from the bypass flow path 120 to the heat
exchanger 136.
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For example, a valve (not shown) may be disposed between the bypass flow path
120
and the heat exchanger 136. The valve may be disposed in the bypass duct outer
wall
opening 124. Alternatively, the plurality of fins 150 may act as a valve and
may be
configured to actuate and selectively open and close to thereby regulate
airflow
through the bypass flow path air inlet 140. In another example, a valve 162
may be
disposed downstream of the bypass air exhaust outlet 146, such as in duct 169.
100231 In another embodiment, one or more engine flow path valves 166, 168,
170
may be used downstream of the engine 101 to regulate air flow from the engine
101 to
the heat exchanger 136. For example, a valve 166 may be disposed between the
engine 101 and the engine air inlet 144, and thus, may be disposed in the
engine air
supply line 154. In another example, a valve 168 may be disposed downstream of
the
heat exchanger 136. For instance, the valve 168 may be downstream of the
engine air
outlet 146 in the bleed air supply line 156. In another example, a valve 170
may be
disposed downstream the bleed air supply line 156 proximate the aircraft
system 164.
100241 Thus, if the cooling system 102 is to be employed, one or more of the
bypass
flow path valves 162 and one or more of the engine flow path valves 166, 168,
170
are opened. If not these valves may be closed.
(0025] By including the cooling system 102 as part of the engine 100, and in
some
embodiments, integrally forming the cooling system 102 as part of the engine
100, air
may flow directly therebetween. Consequently, a cooling system 102 has now
been
provided that is lighter than conventional cooling systems and that may be
implemented into existing aircraft without substantially increasing weight.
Moreover,
the cooling systems may be implemented by adding a minimal number of
additional
components to the aircraft and may be simpler to install than conventional
systems
providing a cost savings.
[0026] While the inventive subject matter has been described with reference to
a
preferred embodiment, it will be understood by those skilled in the art that
various
changes may be made and equivalents may be substituted for elements thereof
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without departing from the scope of the inventive subject matter. In addition,
many
modifications may be made to adapt to a particular situation or material to
the
teachings of the inventive subject matter without departing from the essential
scope
thereof. Therefore, it is intended that the inventive subject matter not be
limited to the
particular embodiment disclosed as the best mode contemplated for carrying out
this
inventive subject matter, but that the inventive subject matter will include
all
embodiments falling within the scope of the appended claims.
